The cartridge consists of a casing, called cartridge case, once built in cardboard or metal, today almost exclusively in plastic.
Inside it houses the gunpowder, an ignition device and a bullet or, in the case of shot, several bullets. Initially the rifles were loaded from the muzzle with a series of maneuvers that limited their functionality. In fact, a little humidity or a breath of wind was enough to make the spark that should have ignited the dust useless.
The discovery of the mercury fulminate overcame the drawback: the chemical compound was closed in a casing placed over a hollow pin and in communication with the charge.
In 1836 the German Nicholas Dreyse manufactured a breech-loading rifle that combined powder and primer. But the real success was obtained by Lefaucheux, inventor, in 1850, of that system that still bears his name today.
The fulminant was placed inside the cartridge and a "pin" that worked as a firing pin, when it was hit by the dog, it ignited the capsule and then made the powder explode. The cartridges, however, had some drawbacks, including that they could burst when falling. Ten years later the English gunsmith Lancaster placed the firing pin in the receiver and then removed it from the cartridge and the fulminant was stuck in the center of the caseback. The birth of the modern rifle had begun.
The first cartridge cases were built with six layers of rolled and glued paper plastic is currently used but there is a return to cardboard precisely because it is easily eliminated. However, it makes its way into the hunter - and some regional laws require it - not to throw the fired shells but keep them until the end of the hunting day.
One side of the cartridge is closed by a case back which is usually made of metal and makes the cartridge itself more solid. In particularly valuable cases at the bottom there is an aluminum coating that avoids the compression of dust. The internal bottom is called notch or buscione (from the French bouchon, cap) and can be conical, semi-conical or flat when the powders are bulky.
In the center of the bottom there is a hole that houses the ignition device also called primer or capsule that contains a substance that catches fire if crushed Inside the cap there is an anvil that acts as a striker The primers are of three types : to double strength and common, covered or discovered.
The powders are divided into two categories: double-based, ie nitrocellulose gelatinized with nitroglycerin, and nitrocellulose. According to the shape, however, they can be laminated, drawn or granular. Based on the ballistic characteristics, they are divided into lively, semi-progressive, progressive and super-progressive. Finally, there are dense, semi-dense and voluminous powders.